This invention relates to easy-opening can ends of the type utilized on beer and beverage cans which permit opening of the cans without the use of a separate tool or opening device.
Heretofore, various easy-opening can ends utilizing pivoting tabs have been proposed. The pivoting tab has been considered to be particularly desirable in that it avoids the necessity for partially preforming a dispensing opening and/or vent hole by scoring or otherwise weakening a predetermined area of the can end. As a consequence, the pivoting tab may be utilized on an all-steel end which does not lend itself to the use of a partially preformed dispensing opening and/or vent hole by scoring or weakening due to the strength of the steel.
U.S. Pat. No. 3,622,055 -- Douty discloses a pivoting tab in a steel can end having a dispensing opening and a vent hole. The tab is pivotally attached to the exterior side of the can end with portions of the tab extending into the dispensing opening and the vent hole and sealingly engaged at the under side of the can end along the edges of the dispensing opening and the vent hole. Can ends of this type may be particularly difficult to open since the seal at the dispensing opening and the vent hole may provide a good deal of resistance. Another can end having a pivoting tab is disclosed in U.S. Pat. No. 3,106,311 -- Fairchild wherein portions of the tab must be removed from positions of sealing engagement with the dispensing opening by pulling upwardly on the tab prior to pivoting to the open position.
Another approach to easy-opening can ends which does not rely upon partially preformed dispensing openings is disclosed in U.S. Pat. No. 3,800,971 -- LaVista wherein the tab comprises a plug which is pushed inwardly for opening. Pushin plugs are also disclosed in copending application Ser. No. 522,097 filed Nov. 8, 1974 and Ser. No. 513,723 filed Oct. 10, 1974 and assigned to the assignee of this invention.